2aff



The solution structure of the Ki67FHA/hNIFK(226-269)3P complex

Overview
The forkhead-associated (FHA) domain of human Ki67 interacts with the human nucleolar protein hNIFK, recognizing a 44-residue fragment, hNIFK226-269, phosphorylated at Thr234. Here we show that high-affinity binding requires sequential phosphorylation by two kinases, CDK1 and GSK3, yielding pThr238, pThr234 and pSer230. We have determined the solution structure of Ki67FHA in complex with the triply phosphorylated peptide hNIFK226-269(3P), revealing not only local recognition of pThr234 but also the extension of the beta-sheet of the FHA domain by the addition of a beta-strand of hNIFK. The structure of an FHA domain in complex with a biologically relevant binding partner provides insights into ligand specificity and potentially links the cancer marker protein Ki67 to a signaling pathway associated with cell fate specification.

About this Structure
2AFF is a Protein complex structure of sequences from Escherichia coli. Full crystallographic information is available from OCA.

Reference
Sequential phosphorylation and multisite interactions characterize specific target recognition by the FHA domain of Ki67., Byeon IJ, Li H, Song H, Gronenborn AM, Tsai MD, Nat Struct Mol Biol. 2005 Nov;12(11):987-93. PMID:16244663

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